From: gay@sfu.ca   
      
   Thomas 'PointedEars' Lahn wrote:   
      
   > Ian wrote:   
   >> Stefan Ram wrote:   
   >>> Jan Panteltje  wrote or quoted:   
   >>>> What are the effects of magnetic field lines on star formation in   
   >>>> galaxies?   
   >>>   
   >>>   These natural magnetic fields in galaxies and their gradients,   
   >>>   I think, are relatively weak. Over long timescales and over larger   
   >>>   spatial regions, their effects can accumulate and become   
   >>>   noticeable. But to drive a spacecraft, you'd need fields that are   
   >>>   fairly strong at the location of the ship and at the moment the   
   >>>   ship is there.   
   >>   
   >> You also need a large _gradient_ of magnetic field.   
   >   
   > What is that even supposed to mean?   
      
   A magnet has a north and a south pole. In a uniform magnetic field,   
   there will be equal and opposite forces on these. To obtain a net   
   force, the magnetic field must be different at the N and S poles. That   
   is, the field must have a non-zero gradient. (Check dictionary, if   
   necessary)   
      
   [unintelligible crap elided.]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)